Marine ignitron



Patented Jan. 12, 1943 MARINE IGNITRO Donald E. Marshall, Allwood, N.J., assignor to- Westnghouse Electric & Manufacturing Company, EastPittsburgh, Pa., a corporation of Pennsylvania Application November 27,1940, Serial No. 367,344

12 Claims.

My invention relates to discharge devices and especially to such devicesutilizing a mercury pool cathode.

An object of my invention is to provide a structure for a mercury pooldischarge device which can be utilized on board ship and other placeswhere excessive tilting of the device, even up to 45, will beexperienced.

Another object of the invention is to locate the ignitor of a mercurypool device so that its relatonship to the surface of the mercury willbe constant even though the device is'tilted at an angle of 45.

Other objects and advantages of the invention will be apparent from thefollowing description and drawing in which:

Fig. 1 is a view in cross section of a preferred embodiment of theinvention with dotted lines illustrating the device tilted at a 45angle.

Fig. 2 is a cross-sectional view illustrating a modification of thestructure of Fig. 1. While my invention may be applied to other types ofdischarge devices utilizing mercury pools, it is especially adapted forthe mercury pool type of device known as an ignitron and employing anigniting electrode of high resistance material partially immersed in themercury pool cathode. One of the problems that has been preventing theapplication of such devices to utilization on board ship andothersituations subject to movement is that as the ship rolls, themercury surface will take various angles and emergent depths relative tothe ignitor. The ignitor may be completely removed from the mercury. Theresult will be that even if the control of the discharge is notcompletely eliminated, at least the characteristics of the ignitingcircuit due to the varying contact of the ignitor with the mercury willbevaried so as to upset the control circuit.

It is accordingly one of the objectsof my invention to maintain therelationshipbetweenthe ignitor and the mercury pool cathode surfaceconstant so that there will be no variation in the control of thedischarge. l

i In Fig. 1 I have disclosed a preferredembodiment of my invention inwhich an envelope, I preferably of steel has a mercury pool cathode Ilin the bottom portion thereof.- The anode I2 preferably of carbon isdiagrammatically illustrated in the upper portion of the casing, andthis anode may have its connection thereto insulatingly sealed throughthe casing I0 in any desired manner. The length of the casing is suchthat the mercury pool will not touch the anode when tilted at a 45angle.

I preferably insert a header I3 to fornil the bottom of this casing I lland. welded thereto. `This upward from the bottornplane I5 of theheader.

,This projection I4 is preferably of conical shape,

and specifically may have the fru'sto-conical shape illustrated, withthe vtop flat portion I6 having a large central hole I'I therein. Aconductor I8 for the ignitor circuit passes through this open.- ing I 'iand has a rod `IS sealed through a glob of glass 26. The rodi I9 isprr'eferablyv of ironnickel-cobalt alloy sold under the trade-name ofKoi/ar, and the glass 20 is preferably borosilicate glass. I

'An eyelet 2| of .the same material as the rod has its circularV edgesealed into the glob 0f glass and surrounds a portion of the rod I9.This eyelet 2| is preferably welded to the top of asteel eyelet 22welded in turn tothe top surface of the top `portion I6 of thefrusto-conical extension I4. If desired, the eyelet 2I could have beenenlarged to be directly welded to the truste-conical extension I4. Therod I9, after passing through the glass 20 sealing the opening throughtheeyelets', is connected to a flexible cable 23 preferably of twistedsteel Wires. This flexible cable 23 is connected in turn to amake-alive24 of high resistance material such as boron or silicon carbide havingits tapered tip 25 immersed at 26iin' the mercury pool cathode Il.

One of the problems which my invention solves is to maintain constantthe depth of `immersion of this ignitingelectrode inthe mercury pool inspite of the tilting of the device through an angle of 45. In order toido this, I surround the Lsteel eyelet 22 with an arbor 2J having alower portion welded or otherwise secured tothis steel eyelet. Thecentral portion of this arbor 2l is in the shape 0f a sphere 28 \vithits horizontal diameter 29 atthe surface of the mercury pool.Surrounding this sphere 29 is a ring-shapedloat- 30 having a plate 3lextendingV towards the sphere of thearbor. This yplate 3l has a centralopening 32 just large enough to be confined by the sphere 28, butpermitting Auniversal lmovement; therearound with thetilting of thedevice. A flange 28 on the upper part of the arbor 2l prevents anymercury from splashing inside the arbor. The arbor 21 and thev eyelet 22could obviously be integral instead of separate pieces, if desired.

This oat preferably has its plate 3l depressed as indicated at 33, andthis platehas openings 34 therethrough for the owing of mercury to therestricted surface inside the ring. On top of the ring is secured aneyelet 35 of iron-nickelcobalt alloy known under the trade name ofKovar, and a globule of glass 36 is sealed thereto. Within this globuleof glass is sealed a rod 31 likewise of this iron-nickel-cobalt alloy,and to this rod is attached a clamp 38 that is secured to the connection39 between the flexible conductor 23 and the high resistance make-alive24. The tip of the ignitor 24 is preferably located in one of theopenings 34 of the dampening ring.

It will be noted that as the discharge device is tipped sideways throughan angle of 45 because of the roll of the ship, the mercury on therighthand side of the device will ow around the conical extension fromthe bottom and flow into the left-hand side, as illustrated by thedotted lines. The level of the mercury will be the same., however, inrelationship to the dampening ring. The point of immersion 26 of theigniting device will remain as it is. The arbor 21 will tilt, but thisis permitted by the opening I9 in the ring. The main effect within thedevice will merely be a flexing of the flexible conductor 23. Themakealive 24 will continue to control the discharge through the devicewith exactly the same characteristics as in the upright position of thedevice because the relationship of the make-alive with the mercury poolhas been changed in no way from the preceding position.

In Fig. 2 I have disclosed a still further modification of the devicethat has preferably the same steel casing I0, mercury pool II, and anodeI2. The bottom header I3' has the same conical, and preferablyfrusto-conical, extension into the mercury. The tapered sides I4 canstart their taper directly from the outer wall in this modificationbecause the make-alive 24 will be maintained at the exact center of themercury pool. The flexible conductor I8 is connected, as in thepreceding modification, to a rod I9 preferably of the ironnickel-cobaltalloy sold under the trade name of Kovan A large globule of borosilicateglass 40 is sealed to this conductor and an eyelet 4I of thisnickel-iron-cobalt alloy has its circular edge sealed into this glassand its other end welded at 42 to the underside of the upper plate I6 ofthe frusto-conical extension I4. This upper plate I6 has a central holeI'I through which the conductor I9 extends. The conductor I9, afterpassing through the opening II, is bent slightly to one side and has anextension 43 to some height above the mercury pool. This extension 43 ofthe rod I9 is also preferably well-covered with an insulating coatingsuch as a continuation 44 of the borosilicate glass from the globule 40to near the end of the extension 43.

To the other end of the rod connection 43 is an arm 45 extending towardsthe axial center of the device. At the axial center this arm 45 isconnected to a rod 46 extending downward and having at its end themake-alive 24, positioned to be immersed at the position 26 thereon forproper depth of immersion in the mercury pool at the axial center of thepool.

In dotted lines is illustrated the position of the device when tiltedthrough a 45 angle. The make-alive 24 and its connections will tilt withthe tube. However, since the point 26 is at the axial center of thetube, the average immersion of the lower tip of the make-alive willremain the same. In other words, the slightly more conacted by a slightwithdrawal of the mercury from tact of the mercury on one side will becounterthe other side of the make-alive. There will, however, be nolarge diierence in immersion of the make-alive from its original uprightposition as there would be if the make-alive were located at a pointother than the axial center of the device.

Both constructions shown embody the feature of the bottom portion ofenvelope III, having the conical formation such that the mercury pool II is comparatively shallow at its central portion and progressivelydeepens away from the central portion. Furthermore, with the envelope inits normal upright position there is a point in the surface plane of themercury on the axis or extended axis of the conical formation whichremains in the surface plane of the pool on tilting the envelope to anangle up to 45 from normal. A further advantageous result from provisionof the conical formation is that its presence as part of the lowerheader provides a large saving in mercury which would otherwise benecessary.

Itis apparent that many further modifications may be made in mypreferred embodiments, and accordingly I desire only such limitations tobe imposed on my invention as are necessitated by the spirit and scopeof the following claims.

I claim:

1. A discharge device comprising an envelope having a mercury poolcathode resting on the bottom portion thereof, the bottom portion ofsaid envelope having a projection producing a comparatively shallowcentral portion of said pool and a deepening of the pool away from saidcentral portion, a connection passing through said central portion, amake-alive electrode connected thereto, means on said projection sealedto and passing said connection through and free from electrical contactwith said projection, means maintaining said make-alive electrode partlyimmersed in the pool in fixed relationship to the normal central portionof the pool, and an anode cooperating with said mercury pool.

2. A discharge device comprising an envelope having a metal bottomportion, a mercury pool therein, said metal bottom having a metalprojection providing a comparatively shallow central portion withgradual deepening of the pool away from said central portion, saidmercury pool having in its surface plane a central point in normalupright position of the envelope, which point remains substantially inthe surface plane of the pool and centrally of the envelope on tiltingthe envelope to an angle up to 45 from normal, a conductor vextendingthrough the projection, insulation insulating said conductor from saidmetal projection, casing and pool, a makealive connected to saidconnection and partially immersed in said pool and maintained withsubstantial constancy of immersion and relation to said point.

3. A discharge device comprising an envelope having a metal bottomportion, a mercury pool therein, said metal bottom having a projectionproviding a comparatively shallow central portion with gradual deepeningof the pool away from said central portion, said mercury pool having inits surface plane a central point in normal upright position of theenvelope, which point remains substantially in the surface plane of thepool and centrally of the envelope on tilting the envelope to an angleup to 45 from normal, a conductor extending through the projection,insulation insulating said conductor from said metal casing and pool, amake-alive connected to said connection and partially immersed in saidpool at a position oifset from the most shallow central portion of themercury pool and maintained with substantial constancy of immersion andrelation to said central point.

4. A metal tank discharge device having a conical upward metalprojection in the bottom portion thereof, a mercury pool on said conicalprojection in electrical contact therewith, a make-alive electrodepartially immersed in said pool and having a connection passing throughand out of contact with said conical projection, and means maintainingsaid make-alive in xed position with respect to the top of said conicalprojection.

5. A metal tank discharge device having an upward projection in thebottom portion thereof, a sleeve on the upper portion of saidprojection, a connection extending through said projection and sleeve, amake-alive attached to said connection, a mercury pool in the bottomportion of said tank reaching said sleeve, a iioat having a universaljoint connection with said sleeve, said make-alive supported by saidfloat.

6. A metal tank discharge device having an upward conical projection inthe bottom portion thereof, a sleeve on the upper portion of saidprojection, a connection extending through said projection and sleeve, amake-alive attached to said connection, a mercury pool in the bottomportion of said tank reaching said sleeve, a float having a universaljoint connection with said sleeve, said make-alive supported by saidiloat.

7. A metal tank discharge device having an upward projectingconstruction from the bottom portion thereof, a spherical portion on theupper portion of said construction, a mercury pool having its surface incontact with said spherical portion, a float on said mercury making'auniversal joint with said spherical. portion, and a makealive secured tosaid iloat.

8. A metal tank discharge device having an upward projectingconstruction from the bottom portion thereof, a spherical portion on theupper portion of said construction, a mercury pool having its surface incontact with said spherical portion, a iloat on said mercury making auniversal joint with said spherical portion, a make-alive secured tosaid float, and a connection from said make-alive extending through saidupward projecting construction.

9. A metal tank discharge device subject to tilting and comprising abottom portion having an upwardly diminishing truncated conical metalprojection of which the axis is normally vertically disposed and ofwhich the conical surface is substantially at an angie of 45 to the saidaxis, a sleeve surrounding an opening in the top portion of saidprojection, insulation sealed to said sleeve, a conductor sealed throughsaid insulation, a mercury pool about said projection completelyimmersing the said projection up to 45? angle tilting of said tank, anda make-alive for said pool attached to said conductor.

10. A metal tank discharge device comprising a bottom portion having anupward truncated conical projection, a sleeve surrounding an opening inthe top portion of said projection, insulation sealed to said sleeve, aconductive rod projecting above the mercury out of contact therewith andsealed through said insulation, a mercury pool about said projection, afloat on said mercury, a make-alive attached to said oat, and a ilexibleconnection from said make-alive to said rod.

11. A metal tank discharge device comprising a bottom portion having anupward truncated conical projection, a sleeve surrounding an opening inthe top portion of said projection, insulation sealed to said sleeve, aconductive rod sealed through said insulation, a mercury pool about saidprojection, a float on said mercury, a makealive attached to said float,and a flexible connection from said make-alive to said rod, a universaljoint between said sleeve and said oat.

12. A discharge device comprising an envelope having a metal bottomportion, a mercury pool therein, said metal bottom having a projectionproviding a comparatively shallow central portion with gradua1 deepeningof the pool away from said central portion, said mercury pool having inits surface plane a central point in normal upright position of theenvelope which remains substantially in the surface plane of the pooland centrally of the envelope on tilting the envelope to an angle up to45 from normal, a conductor extending through the projection, insulationinsulating said conductor from said metal casing and pool, a make-aliveconnected to said connection and partially immersed in said pool at aposition substantially coinciding with said central point in the surfaceplane of the mercury pool, whereby substantially constant immersion ismaintained with varying angular positions up to 45 of said envelope.

DONALD E. MARSHALL.

